• Title/Summary/Keyword: Proportional Hazard Model

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Gamma Knife Radiosurgery for Brain Metastases from Breast Cancer

  • Jo, Kyung Il;Im, Young-Hyuck;Kong, Doo Sik;Seol, Ho Jun;Nam, Do-Hyun;Lee, Jung-Il
    • Journal of Korean Neurosurgical Society
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    • v.54 no.5
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    • pp.399-404
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    • 2013
  • Objective : The authors conducted a retrospective cohort study to determine prognostic factors and treatment outcomes of brain metastases (BM) from breast cancer (BC) after Gamma Knife radiosurgery (GKS). Methods : Pathologic and clinical features, and outcomes were analyzed in a cohort of 62 patients with BM from BC treated by GKS. The Kaplan- Meier method, the log-rank test, and Cox's proportional hazards model were used to assess prognostic factors. Results : Median survival after GKS was 73.0 weeks (95% confidence interval, 46.0-100.1). HER2+ [hazard ratio (HR) 0.441; p=0.045], Karnofsky performance scale (KPS) 70 (RR 0.416; p=0.050) and systemic chemotherapy after GKS (RR 0.282; p=0.001) were found to be a favorable prognostic factor of overall survival. Actuarial local control (LC) rate were 89.5±4.5 and 70.5±6.9 at 6 and 12 months after GKS, respectively. No prognostic factors were found to affect LC rate. Uni- and multivariate analysis revealed that the distant control (DC) rate was higher in patients with; a small number (3) of metastasis (HR 0.300; p=0.045), no known extracranial metastasis (p=0.013, log-rank test), or the HER2+ subtype (HR 0.267; p=0.027). Additional whole brain radiation therapy and metastasis volume were not found to be significantly associated with LC, DC, or overall survival. Conclusion : The treatment outcomes of patients with newly diagnosed BM from BC treated with GKS could be affected primarily by intrinsic subtype, KPS, and systemic chemotherapy. Therapeutic strategy and prognosis scoring system should be individualized based on considerations of intrinsic subtype in addition to traditionally known parameters related to stereotactic radiosurgery.

Association between Cigarette Smoking History and Mortality in 36,446 Health Examinees in Korea

  • Kim, Kyoungwoo;Yoo, Taiwoo;Kim, Yeonju;Choi, Ji-Ho;Myung, Seung-Kwon;Park, Sang-Min;Hong, Yun-Chul;Cho, Belong;Park, Sue K.;Yoo, Keun-Young
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.14
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    • pp.5685-5689
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    • 2014
  • Background: It is well known that smoking is a preventable factor for all-cause mortality; however, it is still questionable how many years after smoking cessation that people will have reduced risk for mortality, in particular in those with a high interest in their own health. We aimed to examine the association between time since quitting smoking and total mortality among past-smokers relative to current smokers. Materials and Methods: We enrolled 36,446 health examinees that voluntarily taken with diverse health check-up packages of high cost burden in 1995-2003 and followed them till death by 2004. The history of cigarette smoking consumption was collected using a self-administrative questionnaire at the first visit time. Mortality risk by smoking cessation years was analyzed using Cox's proportional hazard model. Results: Compared to non-smokers, male smokers over 15 pack-years had higher risk for total mortality (HR=1.60, 95%CI 1.23-2.14). The mortality risk in female smokers with same pack-years was more pronounced than that in male smokers (HR=2.83, 95%CI 1.17-7.04) despite a small number of cases. Compared to current smokers, a decrease of total mortality was observed among those who ceased smoking, and inverse dose-response was found with years after cessation: RR 0.98 (95%CI, 0.64-1.41) (<2 yrs), 0.60 (95%CI, 0.43-0.83) (3-9 yrs), and 0.58 (95%CI, 0.43-0.79) (10 yrs). Conclusions: A reduced risk of total mortality was observed after 3 years of smoking cessation. Our findings suggest that at least 3 years of smoking cessation may contribute to reduce premature mortality among Asian men.

Cigarette Smoking and Gastric Cancer Risk in a Community-based Cohort Study in Korea (흡연과 위암 발생의 관련성에 관한 지역사회 기반의 코호트 연구)

  • Kim, Yeon-Ju;Shin, Ae-Sun;Gwack, Jin;Jun, Jae-Kwan;Park, Sue-Kyung;Kang, Dae-Hee;Shin, Hai-Rim;Chang, Soung-Hoon;Yoo, Keun-Young
    • Journal of Preventive Medicine and Public Health
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    • v.40 no.6
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    • pp.467-474
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    • 2007
  • Objectives : Gastric cancer is the most common incident cancer in Korea. Although Helicobacter pylori infection is the most important risk factor for the development of gastric cancer, cigarette smoking has also been suggested to play an important role in the development of gastric cancer. The objective of this study is to evaluate the relationship between cigarette smoking and gastric cancer risk in a Korean population. Methods : The study population consisted of 13,785 subjects who had been enrolled in the Korean Multi-Center Career Cohort between 1993 and 2002. As of December 2002, 139 incident gastric cancer cases were ascertained through the Korea Central Cancer Registry and the National Death Certificate Database. Relative risks (RR) and 95% confidence intervals (CI) for gastric cancer were estimated using Cox#s proportional hazard model adjusted for age, education, alcohol drinking status and history of gastritis or ulcer. Results : Significant dose-response relationships were observed between the duration of smoking and the risk of gastric cancer among the male subjects in comparison to non-smokers: men who smoked for 20-39 years had a 2.09-fold (95% CI 1.00-4.38) increase, and those who smoked for more than 40 years had a 3.13-fold (95% CI 1.59-6.17) increase in the risk of gastric cancer (Ptrend<0.01). Conclusions : This study suggests that a longer duration of cigarette smoking may increase the risk of gastric cancer development in a dose-response manner in Korean men. The association between smoking and gastric cancer risk in women should be verified in future studies with a larger number of cases.

Association between BMI and Mortality - Kangwha cohort study - (BMI와 사망과의 관련성 - 강화 코호트 연구 -)

  • Yoon, Soo-Jin;Yi, Sang-Wook;Kim, Soh-Yoon;Lee, Soon-Young;Park, Yun-Hee;Sohn, Tae-Yong;Ohrr, Hee-Choul
    • Journal of Preventive Medicine and Public Health
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    • v.33 no.4
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    • pp.459-468
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    • 2000
  • Objectives : To investigate the association between BMI and Mortality. Methods : This study was based on the analysis and assembly of the 'Kangwha Cohort Study', previously conducted by the Department of Preventive Medicine, Yonsei University. A total of 2,696 males and 3,595 females were followed for almost ten years and ten months from March 1985 to January 1996, a total of whom 2,420 died during this period. The Cox's proportional hazards regression model was used to analyze this data. Results : We found a U-shaped relationship between BMI and mortality among the aged men in the Kangwha cohort. The hazard ratio of dying was adjusted for age, marital status, occupation, self cognitive health level, chronic disease, smoking, and alcohol frequency, then sorted by body mass index into the following groups; less than 10.5, 18.5 to less than 21.0, 21.0 to less than 23.5, 23.5 to less than 26.0 and greater than or equal to 26. The corresponding ratios for men were 1.81(1.50-2.19, 95%CI), 1.31(1.14-1.51, 95%CI), 1.0(referent), 1.05(0.87-1.26, 95%CI) and 1.39(1.09-1.76, 95%CI), respectively. And for women, 1.46(1.19-1.78), 1.12(0.95-1.31, 95%CI), 1.0(referent), 1.00(0.84-1.20, 95%CI) and 1.09(0.89-1.34, 95%CI), respectively. Conclusions : The risk of death among aged men in Kangwha increased in the under and overweight groups. The relationship between BMl and mortality has been well studied in Western populations, but little is known about the association between BMI and mortality in our country. So, on the basis of this study, it is apparent that more studies of the relationship between BMI and mortality will be needed for future work.

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Efficacy of First-Line Targeted Therapy in Real-World Korean Patients with Metastatic Renal Cell Carcinoma: Focus on Sunitinib and Pazopanib

  • Kim, Myung Soo;Chung, Ho Seok;Hwang, Eu Chang;Jung, Seung Il;Kwon, Dong Deuk;Hwang, Jun Eul;Bae, Woo Kyun;Park, Jae Young;Jeong, Chang Wook;Kwak, Cheol;Song, Cheryn;Seo, Seong Il;Byun, Seok-Soo;Hong, Sung-Hoo;Chung, Jinsoo
    • Journal of Korean Medical Science
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    • v.33 no.51
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    • pp.325.1-325.10
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    • 2018
  • Background: To evaluate survival outcomes and prognostic factors for overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC) who received sunitinib (SU) and pazopanib (PZ) as first-line therapy in real-world Korean clinical practice. Methods: Data of 554 patients with mRCC who received SU or PZ at eight institutions between 2012 and 2016 were retrospectively reviewed. Based on the targeted therapy, the patients were divided into SU (n = 293) or PZ (n = 261) groups, and the clinicopathological variables and survival rates of the two groups were compared. A multivariable Cox proportional hazard model was used to determine the prognostic factors for OS. Results: The median follow-up was 16.4 months (interquartile range, 8.3-31.3). Patients in the PZ group were older, and no significant difference was observed in the performance status (PS) between the two groups. In the SU group, the dose reduction rate was higher and the incidence of grade 3 toxicity was more frequent. The objective response rates were comparable between the two groups (SU, 32.1% vs. PZ, 36.4%). OS did not differ significantly between the two groups (SU, 36.5 months vs. PZ, 40.2 months; log-rank, P = 0.955). Body mass index, Eastern Cooperative Oncology Group PS > 2, synchronous metastasis, poor Heng risk criteria, and liver and bone metastases were associated with a shorter OS. Conclusion: Our real-world data of Korean patients with mRCC suggested that SU and PZ had similar efficacies as first-line therapy for mRCC. However, PZ was better tolerated than SU in Korean patients.

A Study on the Elapsed Time to Resale of Pre-Completion Apartment Ownership (아파트 분양권의 전매기간에 관한 연구)

  • Song, Seon Ju;Shin, Jong Chil
    • Korea Real Estate Review
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    • v.27 no.3
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    • pp.103-118
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    • 2017
  • Under the ownership pre-sale system in the South Korean apartment market, developers can sell apartment ownerships as soon as they start to construct an apartment complex. In the South Korean apartment market, people call this kind of ownership "Bun-yang right." There is a time difference between ownership sale and apartment completion under the ownership pre-sale system. The pre-completion apartment ownerships can be resold to third parties until the apartment complexes are completed, which is called "Geon-mae" of the Bun-yang right. Using survival analysis, this research analyzed the elapsed time between ownership purchase and resale to a third party using 48,316 apartment units nationwide in the 192 complexes supplied from 2000 to 2016. Specifically, this study analyzed the influence of the real estate policy, contract term, location, apartment complex, and unit characteristics on the elapsed time between ownership purchase and resale to a third party. The empirical analysis revealed that the real estate policy and contract term characteristics have a significant effect on the elapsed time between ownership purchase and resale to a third party. Also, this study confirmed that the product characteristics, such as the location and apartment complex and unit characteristics, have an influence on the elapsed time between ownership purchase and resale to a third party.

Association between Participation in Social Activities and Mortality (중고령층 집단의 사회활동 참여와 사망률의 연관성 분석)

  • Kim, Young Guen;Yang, Jeong Min;Kim, Jae Hyun
    • Health Policy and Management
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    • v.31 no.4
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    • pp.462-471
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    • 2021
  • Background: The purpose of this study was to identify the association between participation in social activities and mortality rates for those aged 45 aged and older in Korea. Methods: In this study, the 1st to 6th Korea Longitude Study of Aging was used to analyze 10,217 people excluding missing values among middle and old age groups aged 45 or older. The scope of social activities was classified into "religious gatherings," "religious gatherings," "leisure/cultural/sports-related organizations," and "clubs/hometowns/religious associations," and analyzed using a chi-square test and Cox proportional risk model. Results: In the case of non-participating groups in religious activities, the mortality rate was 1.24 times higher (hazard ratio [HR], 1.24; p=0.000) than those of the participating group. The non-participating group of social gatherings had a 1.27 times higher mortality rate (HR, 1.27; p<0.0001) than the participating group. In addition, the mortality rate of non-participating groups related to leisure/cultural/sports was 1.79 times higher (HR, 1.79; p=0.000). The mortality rate of the group that did not participate in the alumni association/festival/folklore society was 1.51 times higher than that of the participating group (HR, 1.51; p<0.0001). As a result of correcting the control variable to analyze the relationship between the number of participants in social activities and the mortality rate, the mortality rate of the group participating in one or less social activities was 2.26 times higher (HR, 2.26; p<0.0001) compared to the four or more social activity participating groups, and the mortality rate of the 1-3 social activities was 1.64 times higher (HR, 1.64; p<0.0001). Conclusion: As a result of the study, it was found that participation in social activities of the middle-aged and elderly groups was effective in reducing mortality, and in particular, it was found that there was a strong relationship with mortality in less than one social activity group. Therefore, it is intended to provide an academic basis for lowering the mortality rate of the group in line with the continuous improvement of domestic social activity participation conditions, and through this, this study can be expected to serve as a policy and institutional basis for lowering the mortality rate of the group.

Preoperative Risk Factors for Pathologic N2 Metastasis in Positron Emission Tomography-Computed Tomography-Diagnosed N0-1 Non-Small Cell Lung Cancer

  • Yoon, Tae-hong;Lee, Chul-ho;Park, Ki-sung;Bae, Chi-hoon;Cho, Jun-Woo;Jang, Jae-seok
    • Journal of Chest Surgery
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    • v.52 no.4
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    • pp.221-226
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    • 2019
  • Background: Accurate mediastinal lymph node staging is vital for the optimal therapy and prognostication of patients with lung cancer. This study aimed to determine the preoperative risk factors for pN2 disease, as well as its incidence and long-term outcomes, in patients with clinical N0-1 non-small cell lung cancer. Methods: We retrospectively analyzed patients who were treated surgically for primary non-small cell lung cancer from November 2005 to December 2014. Patients staged as clinical N0-1 via chest computed tomography (CT) and positron emission tomography (PET)-CT were divided into two groups (pN0-1 and pN2) and compared. Results: In a univariate analysis, the significant preoperative risk factors for pN2 included a large tumor size (p=0.083), high maximum standard uptake value on PET (p<0.001), and central location of the tumor (p<0.001). In a multivariate analysis, central location of the tumor (p<0.001) remained a significant preoperative risk factor for pN2 status. The 5-year overall survival rates were 75% and 22.9% in the pN0-1 and pN2 groups, respectively, and 50% and 78.2% in the patients with centrally located and peripherally located tumors, respectively. In a Cox proportional hazard model, central location of the tumor increased the risk of death by 3.4-fold (p<0.001). Conclusion: More invasive procedures should be considered when preoperative risk factors are identified in order to improve the efficacy of diagnostic and therapeutic plans and, consequently, the patient's prognosis.

Leverage and Corporate Failure: Analysis of Leverage Impact according to Company Size through Survival Analysis (레버리지와 기업실패: 생존분석을 응용한 기업규모에 따른 레버리지 영향분석)

  • Kim, Bong-Min;Kim, Byoung-Gon;Kim, Dong-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.1
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    • pp.275-284
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    • 2021
  • Survival analysis was used to analyze whether there is a difference in the effect of leverage on corporate failure according to the firm size. A total of 25,250 (year-company) companies listed on the Korea Stock Exchange and KOSDAQ market from 1999 to 2019 were analyzed. First, the increase in leverage generally acts as a factor that increases the possibility of corporate failure. On the other hand, the increase in the trade payable ratio lowered the possibility of failure of the company. The increase in corporate trade payable was perceived as a factor in reducing the possibility of corporate failure because it was considered the active development of business activities or active use of interest-free debt rather than leading to an increase in corporate risk. Second, a higher leverage ratio and trade payable ratio in large firms lowered the possibility of corporate failure. In the SMEs, all types of leverage increases are a factor that increases corporate failure. Overall, the effect of leverage on corporate failure differs according to the size of the company.

Trade Payable and Corporate Failure: Analysis of Trade Payable Impact according to Company Size through Survival Analysis (매입채무와 기업실패: 생존분석을 응용한 기업규모에 따른 매입채무 영향분석)

  • Kim, Bong-Min;Kim, So Ra
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.6
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    • pp.283-290
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    • 2021
  • Survival analysis was used to determine whether there are differences in the impact of trade payables on business failure according to the size of the company. A total of 41,781 firms from 1999 to 2019 were analyzed. The analysis period was divided into the entire period and before and after the financial crisis. The trade payable ratio is a proxy variable. The increase in trade payables over the entire period increases the possibility of business failure of Small and Medium Enterprises (SMEs). However, in large firms, a significant relationship between the increase in the trade payable ratio and the possibility of corporate failure could not be confirmed. Second, in SMEs during the sub-periods of 1999-2007 and 2009-2019, it was found that an increase in trade payables acts as a factor that increases the possibility of corporate failure. However, in large corporations, the increase in trade payables in the period from 2009 to 2019 has been shown to reduce the rate of failure. An increase in trade payables is recognized as the active development of business activities or the active use of interest-free debt. Therefore, it was confirmed that the impact of trade payables on corporate failure differs depending on the size of the company.